This invention relates to the field of remote energy-emitting source location through passive received signal processing.
Although radio locating has been used since the early days of radio, current military apparatus with its limited output signal durations and the availability of computerized signal processing, faster analog to digital conversion apparatus and a need to accomplish rapid accurate signal locations from a moving vehicle provide opportunity for improvement in this art.
Present aircraft based radio frequency emitter locating methods for example require use of two platforms to obtain angle and range data relating to a radio frequency emitting energy source or one platform flying for some seconds to obtain a multiple line of bearings (i.e., multiple angles of arrivals). In both of these cases range is determined by an intersection on multiple line of bearings. In this invention precisely measured time difference of arrival and a single aircraft are used to determine line of bearing to an emitter and time difference of arrival rate at this aircraft is used to determine emitter range.